US president Barack Obama said on Tuesday that Republican presidential nominee Donald Trump's comments on a 2005 videotape about groping women would disqualify him from even a job at a convenience store.

Speaking at a campaign rally in Greensboro, North Carolina, for Democratic presidential nominee Hillary Clinton, Mr Obama said that the choice was clear in the November 8 election even before the tape was leaked last week showing Mr Trump speaking crudely about women.

"Now you find a situation in which the guy says stuff that nobody would find tolerable if they were applying for a job at 7-Eleven," Mr Obama told the crowd, referring to the convenience store chain.

The Republican candidate said during Sunday night's presidential debate that he was embarrassed by the video, but dismissed it as "locker room talk."

Mr Obama also criticised some Republicans who have condemned the remarks but are still backing the New York businessman.

"The fact that now you've got people saying: 'We strongly disagree, we really disapprove ... but we're still endorsing him.' They still think he should be president, that doesn't make sense to me," Mr Obama said.

Earlier on Tuesday, White House spokesman Josh Earnest condemned the "repugnant remarks" in the recording, saying those actions would constitute sexual assault.

"The president found the tape as repugnant as most Americans did," said White House spokesman Josh Earnest.

Mr Earnest said that the turmoil in the Republican Party isn't surprising. He said Republicans have spent more than seven years prioritising opposition to Mr Obama over facts or true conservative principles. "You reap what you sow," he told reporters on Air Force One.

House speaker Paul Ryan and other high profile Republicans have distanced themselves from Mr Trump since a 2005 video surfaced on Friday showing him bragging crudely to a reporter about groping women and making unwanted sexual advances.

On Tuesday Mr Trump lashed out at Mr Ryan, saying he's sick and tired of fellow Republicans abandoning his candidacy and doesn't want their support anyway.

"The fact is, I think we should get support and we don't get the support from guys like Paul Ryan," the GOP nominee told Fox News Channel's The O'Reilly Factor. "I'm just tired of non-support."

Mr Trump said that Mr Ryan has been overly sensitive, complaining, "if you sneeze he calls up and announces, isn't that a terrible thing." The nominee added that he doesn't want or care about the house speaker's support.